Slitting press



May 14, 1957 4 Sheets-Sheet 1- Filed Sept. 5, 1954 m N R K w T WMA Z M DH. \8 \2 1 mm 7 May 14, 1957 4 Sheets-Sheet 2 Filed Sept. 3, 1954 8 2 9 4 T m 4. w raw I 8 5 7. 5 w 0 Hm t w T. a z r w a. 5 79 mi 0 8 1 ,5 5 7 9 4 w 4 INVENTOR. Mam cc 40 Dario D. MAIOCCHI SLITTING PRESS May 14, 1957 4 Shets-Sheet 5 Filed Sept. 3. 1954 fir TOR/V5 y.

A! V/// ////////////A SLITTING PRESS Dario Maiocchi, Los Angeles, Calif.

Application September 3, 1954, Serial No. 454,090

13 Claims. (Cl. 164-94) This invention relates to a device for cutting slits in sheet material, and'is-particularly concern'edwitha novel apparatus for forming slits of various sizes at any desired angle in a sheet material such as paper or plastic, and which apparatus is particularly useful in the clothing industry for cutting clothes patterns.

One object of the invention isthe provision of a versatile device for forming slits in. sheet material of varying widths, and for forming such slits at various angles to' each other, with a minimum amount of adjustment of the device for this purpose.

Another object is the design of a slitting press which is readily adjustable to form slits of varying'lengths.

A still further object is to provide a slitting device having a slitting blade which permits the blade to form a clean slit in the work piece without producing: ragged edges, while avoiding sticking of the blade to the work piece during withdrawal of the blade fromv the slit so formed.

Yet another object is to afford means on said slitting device to permit the interchangeable use of slitting blades ment transversely of the plane of the Work piece and means is provided to actuate the blade to pierce the work piece and form the desired slit.

The slitting blade is mounted in a plane disposed at an angle to the longitudinal axis of the frame in order to permit the use of work pieces of various Widths and so that the position of the work piece can be readily shifted to change the angle of the slits formed therein. The slitting blade has a series of cutting serrations at its lower end, each of the serrations having a curved or inclined edge and forming a sharp point at its lower extremity. The individual serrations are preferably verti cally spaced at different heights on the blade and are particularly designed in the foregoing. manner so that the blade does not stick in the work piece and a clean sharp slit is formed therein.

An adjustable means is provided to selectively permit one or more of the serrations on the blade to pierce the Work piece so as to produce slits of the desired length, which can vary from a length corresponding to the length of one serration to a length corresponding to the total length of all of the serrations. Means is also furnished to permit my device to interchangeably accommodate slitting blades of different thicknesses inorder to form slits of varying'widths. Such means is in the form of an adjustable die or plate structure.

Patented May 14, 1957 Below is described a preferred embodiment of the invention taken in connection with the accompanying drawings, wherein:

Fig. 1 is an elevational assembly view of my device;

Fig. 1a is a plan view of the device of Fig. l, partly broken away for clarity;

Fig. 2 is a section taken on line 2- 2'of' Fig. 1;

Fig. 3 isan illustration of various configurations which can be made by forming'slits in a work piece using my device;

Fig. 4 is an enlarged elevational' view taken on line 4-4 of Fig. 1a; certain parts being omitted for clarity;

Fig: 5 is afragmentary horizontal section taken on line 5'-'--5 of Fig; 4;

Fig. 6 is an elevational'view of a detail'of the invention device;

Fig. 7 isa section-of a'portion of the detail of Fig. 6;

Fig. 8-'is a plan viewof' another detail of" my device;

Fig. 9 is aview'taken on line 9 9 of Fig. 5 with the movable plate and stop members thereon rotated to a different position fromthat shown in Fig. 5; I

Fig. 10 is a View taken on line lit-10 of Fig. 9;

Fig. 11' is'a perspective view of certain details of my device;

Fig. 12 is a modification of the blade shown in Figs. 1- and 4;

Fig. 13 is an enlarged vertical section on line 13 13 of-Fig. 1 deleting certain parts and showing others in full;

Fig. 14'is a fragmentary eniarge'd elevation in section ofthe lever and blade actuating structure of my invention, certain parts being shown in full;

Fig. 1-5 is an end view taken on line 15-15 of Fig. 14;

Fig; 16 is a modification of the structure shown in Fig. 10;'and

Fig. 17 is another modification of slitting blade.

Referring to Fig. I of'the drawings, my device comprises an elongated frame 20 having a base member 21 and an upper member 22 formed integral at one end 23 with the base member. The upper frame member 22- overhangs and as approximately coextensive with the base member 21', leaving an elongated space 24 be- .tweenthe members 21 and 22 for passage of a Work piece 25 to which a series of slits is to be cut, for example, to make a clothing pattern. The upper surface 26" of the base member 21 is inclined downwardly toward the free working end 27 thereof. Outwardly extending feet 28 are connected to the lower portion of the base member to aid in maintaining the device in an upright position while in use, e. g., on the surface of a table, work bench or other support. In the space 24 adjacent the juncture of'base member 21 and the upper frame member 22 is a V'-shaped guide or end wall 29 having sides'3il and 31 which form an acute angle, e. g., about 45 with the longitudinal axis of the frame 20. V-shaped wall 2? is provided for a purpose pointed out hereinafter. The'frame 20 is conveniently made in the form of a hollow casting, members 21 and 22 having a substantially reotangular'or square cross section, as seen in Fig. 2.

The" base member 21 has integrally connected to the outer free endthereof a block 32 having an upper working surface 33 formed as an extension of the surface 26 of base member 21, surface 33 being essentially horizontal'. The outer end 27 of the block is positioned at anangle to the longitudinal axis of frame 20, preferably at about a 45 angle to such-axis, as seen in Fig. 1a; for reasons hereinafter noted. Surface 33 has aslot 34 therein (see Fig. 10), and disposed on surface 33 on opposite sides of a slot 34 are a pair of plates 35 positioned parallel to such slot and forming a second slot or space 36* between the adjacent parallel edges 37 of the plates, the second slot 36 being in alignment over slot 34, and being usually narrower than slot 34. Slots 36 and 34 are provided to allow passage of the knife or slitting blade 62 therethrough, as will be described more fully hereinafter. The axes of slots 34 and 36, and plates 35 are parallel to the outer end 27 of block 32, and hence it is noted that slots 34 and 36 are also positioned at preferably a 45 angle to the longitudinal axis of frame 20.

The width of slot 36 is made slightly larger than the thickness of the slitting blade 62 so as to permit just sufficient clearance for the blade to pass through this slot. This aids the formation of a clean slit in the work piece 25 which is positioned over the plates 35 as seen in Fig. 1. Plates 35 are adjustable to vary the width of slot 36 to accommodate slitting blades of difierent thicknesses for formation of narrower or thicker slits in the work piece. "For this purpose, each of plates 35 has a pair of transverse slots 39 which accommodate bolt and nut assemblies 40 passing into block 32. By loosening the nuts 40. the plates 35 may be positioned closer together or farther apart to change the distance between the adjacent edges 37 of the plates and hence the width of slot 36. A slot 41 (see Fig. 1) is provided in the outer end 27 of the block 32, to permit manipulation of the nuts of the fasteners 40.

On the outer free end of the upper member 22 of frame 20 is supported a bracket in the form of an angle member 45 (see Figs. 1a and the sides 46 and 47 of such angle member being in a lane perpendicular to the plane of the upper surface 33 of block 32. The lower end of angle member 45 is spaced as at 48 from the adiacent block surface 33 to permit passage of the work piece 25 between the lower end of the angle member and such block surface. Flanges 49 and 49' are integrally connected near the outer end of each of sides 46 and 47, respectivelv, of angle member 45. Mounted on flanges 49 and 49' by means of screws 50 are a pair of guide plates 51. the plates being coplanar in a plane per endicular to the block surface 33, and the plane of such plates being positioned at an acute an le to the axis of frame and substantially in line with the slot 36 below. and parallel to the outer end 27 of block 32.

A blade support block 55 is mounted for vertical sliding movement along the adiacent inner edges 56 of plates 51 by the provision of longitudinal grooves 57 (see Fig. 5) formed in opposite outer surfaces 58 of the support block 55, such grooves mating with the adjacent inner ends 59 of guide plates 51. Secured by means of screws 60 in a recess 61 formed on the front face of support block 55 is a slitting blade 62. the screws passing through longitudinal slots 63 (see Fig. 4) formed adjacent the upper edge 64 of the blade. Slots 63 ermit of vertical adjustment of the blade on block 55. It is seen that the plane of blade 62 is disposed at an acute angle to the lon itudinal axis of frame 20. equal to the angle formed by the end 27 of block 32 with such axis, that is, preferably about 45 to this axis, blade 62 being mounted above and directly in line over slots 36 and 34. Hence, on vertical downward movement of support block 55, slitting blade 62 will be carried downwardly with block 55 to piece the work piece and pass through slots 36 and 34, as seen in Fig. 13.

The knife blade 62 and slots 34 and 36 are disposed at the approximately 45 angle to the axis of frame 20, as previously noted, to facilitate turning the work piece 25 positioned in spaces 24 and 48, in various positions so as to produce a series of slits in the work piece of any desired geometrical configuration as illustrated in Fig. 3. Positioning of blade 62 at an angle to the frame, particularly at a 45 angle thereto, also facilitates passage and guidance of work pieces of different widths through my device by running the work piece along either in a direction normal to the axis of the frame, e. g., using the apex 63' of the V-shaped end wall 29 as a guide for one edge of the work piece, or in a direction at various angles to the frame, e. g., at an angle of say about 45 thereto, using the s1des 30 and 31 of the V-shaped end wall 29 as guides for one edge of the sheet forming the work piece.

The slitting blade 62 (see Fig. 4) has a series of serrations or cutting edges, shown as four in number, 66, 67, 68 and 69, at the bottom of the blade. These serrations are of graduated height, serrations 66 to 68 each having a lower edge providing an effective work cutting portion 69' inclined downwardly at an acute angle to the horizontal, and terminating at its lower end in a leading work piercing point 70. The preferred angle of edges 69 is between about 20 and 30 to the horizontal, and all of the edges 69' need not be positioned at the same angle. Further, the serrations may have different lengths, referring to a dimension measured transversely of the blade 62 as seen in Fig. 4. In the embodiment shown, serration 66 is longer than 67, serration 67 is longer than 68, and 68 is longer than 69. Vertical edges 71 connect the adjacent serrations. The lowermost serration 69 is wedge shaped, and is designed in this manner to facilitate initial piercing of the work piece, since it is apparent that this serration will be the first of the serrations to make contact with the Work piece. Following initial piercing by serration 69, the other serrations can each be made selectively to pierce the work piece in succession from serration 68 finally to serration 66, the point 70 of each of the serrations puncturing the work piece first to initiate formation of the slit produced by the respective serrations. The design of the blade and its individual serrations permits easy piercing and slitting of the work piece to form clean slits without sticking of the blade to the work piece during the process of removal of the blade therefrom. It should also be noted that the lowermost point of each effective work cutting portion 69 is spaced upwardly from the uppermost point on the next lower cutting portion 69, to permit a cut by one complete cutting portion before the work is pierced by a succeeding serration.

A bracket (see Figs. 1 and 14) is connected at its lower end to a triangular shaped plate 76 in turn attached to the top of angle member 45 by screws 77. A lever 78 is pivotally connected at one end by means of pin 79 to an upwardly curved portion 88 of bracket 75. The lower surface of an enlarged portion 81 of lever 78, located near pivot point 79, makes contact with the upper end of a plunger 82 (see Figs. 13 and 14) biased upwardly by spring 83 located in a bore 84 in bracket 75, through which plunger 82 passes. Spring 83 encircles the lower reduced portion 85 of plunger 82, abutting a shoulder 86 at the bottom of the bore and a shoulder 87 on the lower end of the top portion 88 of the plunger. Attached to the bottom of portion 85 of the plunger is a short member 89 of reduced diameter, to the lower end of which is connected a washer 99.

As seen in Figs. 4 and ll, member 89 is received within a slot 91 of a'plate 92 attached by means of screws 93 within a recess 94 in the top of block 55, and washer is disposed in a recess 95 in block 55 below plate 92. The width of slot 91 is slightly greater than the diameter of the reduced member 89, but smaller than washer 90, so that the upper surface of the washer makes contact with the lower surface of plate 92 to thus lock the block 55 and the blade 62 supported thereby, to the lower end of the plunger 82. In this manner vertical move ment of plunger 82 in response to manual actuation of the lever 78, causes vertical movement of block 55 and blade 62. The spring 83 normally urges block 55 and the slot 102 is formed in the lower portion of side wall 46 just above base plate 9%. Slot 162 is provided: to receive the rear portion of movable plate 1%, finger grip llll extending exteriorly of angle member 45, as more clearly seen in Fig. 5.

A lug 105 consisting of three adjacent integral stop members 1%, Hi7 and 1438', arranged in an arc, is integrally formed along the front arcuate periphery 169 of the movable plate iii-"3 These stop members are of different lengths or heights, as seen in Figs. 6 and 9, stop it)? being longer or higher than intermediate step 167, and stop it extending above stop 106. The stop tea, as seen in Pig. 7, is hollow and contains a spring 199 and a pair of balls lllil and ill at opposite ends of the spring, this assembly acting as a latching detent to lock movable plate Eltltl in one of four positions with respect to base plate Q8. The latter has a series of four semicircular recesses 112, 113, 114 and 115 therein, as seen in Fig. 8, these recesses being arranged in an are directly below lug 1% with its stop members 106 to 1%. Ball lit of the detent mechanism contained in stop 1.33 is receivable in each of recesses 112 to 115- on. pivotal movement of plate 1%, to lock the plate in any one of four positions for the purpose hereinafter pointed out.

When movable plate it'll} is in the position shown.-

in Fig. 5, the ball detent 1110 is resting in recess. H5, locking the plate lilo in the position of Fig. 5 with none of the stops 1%, lb? or 1% located directly below the blade support block 55. With stop lug 105 in this position, on pushing lever 78 downward against the action or, spring $3, block will carry blade 62 downward until the bottom 55' of the block 55 makes contact with the base plate @8. At this time the. knife blade 62, will have moved to a position where all of. the four serrations 66 to 69 will have moved down sufi'iciently, that is, to the dotted line 12b in Fig. 13, to pierce the: work piece 25 and form a slit therein of a length equal to the total length of all four serrations 66 to 69, measured transversely of blade 62. On release of lever 78, spring 83 retracts block 55 and blade 62, i. e., causes'thern to be urged upward, withdrawing blade 62 from the work piece and bringing block 55 and blade 62 back to their original starting positions, as seen in Fig. 4;

it plate tee is now pivoted counterclockwise from its position in. Fig. 5 so as to rotate lug 135 until detent lid drops into recess 114 on plate 98, the shortest stop 1% will now be positioned directly below block 55 but spaced vertically from the bottom 55 thereof. It lever 73 is now actuated until block 55 is lowered into contact with the upper surface of stop res, the blade 62 will have moved to a position where only the three serrations 7, 68 and 69 have descended sufficiently to pierce the work piece to form a slit having a length equal to the total length of all three of these serrations.

It plate illtl is now pivoted counterclockwise still further to rotate lug m5 until detent llll drops into recess 113 on plate 98, the intermediate stop 167 will be located below block 55 but spaced vertically from the bottom 55 thereof. On actuation of lever 78 to lower the block into contact with the upper surface of stop 197, the blade 62 will have moved to a position where only the two serrations 63 and so have descended sufiiciently to pierce the work piece 25 to form a slit having a length equal to the total length of these two serrations.

Finally, if plate lilo is now pivoted counterclockwise still further to rotate lug 105 until detent llil drops into recess 11.2 on plate 98, the. tallest stop 103 will now be disposed directly below block 55 but spaced from the bottom 55 thereof. When lever 78 is now actuated to cause block 55 to descend and make contact with the upper surface of stop 108 (see'Fig. 11), the blade 2 will have moved to a position where only the first lowermost serration 69 has descended. sufiiciently to pierce the work piece 25 toform: a. slit having. alength equal to the length of serration 69.

In this manner it is seen that my device is highly versatile and can be used to form all manner of geometrical shapes as seen in Fig. 3, by selectively changing the length of the slit-s formed in the work piece and by rotating or moving the latter about in difierent directions beneath the blade 62. Thus, for example, if it is desired to make the cross 125' of Pig. 3, e. g., for location of a button hole in a clothing pattern, the paper or plastic work sheet 25 is positioned so that one side edge is in aligned contact with side 31 of the V-shaped guide 29, and the slit 126 is formed in the sheet 25 as described above. The sheet is then turned to place the above noted edge thereof in aligned Contact with the other side 3% of the guide 29. Since sides 3%] and 31 are positioned at about a angle to each other, the sheet will have automatically been rotated at right angles from its original position. A slit 127 is now made over slit 126 to form the cross Referring to Fig. 12, there is shown here a modifica- [ion of the slitting blade 62 of Fig. 4. In the modified blade 121 the lower end of the blade consists of curved serrations 122, 123, 124 and 125 of graduated height instead of the sawtooth type serrations of blade 62.

Referring now to Fig. 16, this structure is a modification of the movable plate structure shown in Fig. 10. In Fig. 16, a plate 130 is secured by means of screws 131 to the top of base plate 33 of the block 32. A notch 132 formed along the longitudinal edge 133 of plate 130 is disposed directly above the slot 3 in the base plate 33, permitting passage of the slitting blade, for example, blade 62, downwardly through notch 132 and slot 34 for piercingthe work piece. An adjustable plate 134- having a length slightly shorter than the length of notch 132 is positioned with an edge 13:5 disposed within notch 132, and is secured to plate 3-3 by screws 136 passing through transverse slots 137. By loosening screws 136, plate 134- can be moved toward or away from the inner longitudinal edge 138 of notch 132,, so as to increase or decrease the width of the space 139 between such edge and plate 134 in order to accommodate blades of different thicknesses.

In Fig. 17 is shown another modification of slitting blade which has been found particularly useful. The blade 14-0 of this modification is symmetrical about its central axis X-X, and has three graduated serrations 141, 142 and 143 at its lower end, similar to serrations 66, 67 and 63 of the blade shown in Fig. 4, serrations Ml to 143 being located on one side of axis X-X. Blade 140 also has three graduated serrations 141', 142' and 143' at its lower end, and located on the opposite side of axis XX from serrations 141 to M3, the former serrations being mirror images of the latter. Blade 149 may be employed to form slits having a length, measured transversely of axis X--X, equal to the total length of serrations 143 and M3; or of 142, 143, 143 and 142; or of 14-1, 142, 143, 143, i422, and 141'.

While I have described a particular embodiment of my invention for the purpose of illustration, it should be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

I claim:

1. A device comprising an elongated base member, an elongated upper member overhanging said base memher and forming a space between said members for passage of a work piece through said space, a blade supported for movement on said upper member in a direction transversely of said elongated members toward and away from the base member, said blade having a plurality of cutting edges along the lower end thereof each having an effective work cutting portion terminating in a lowermost and leading work piercing point, successive work cutting portions being stepped away from the base member with the leading Work piercing point of one eifective cutting portion being spaced upwardly from the uppermost section of the preceding effective cutting portion, whereby the work piece is cut by one complete cutting portion before being pierced by any part of the next succeeding cutting portion and the cut of each cutting edge is commenced by a work piercing point, and means for adjusting the extent of said movement of said blade to cause a selected number of said cutting portions to pierce said work piece.

2. A device as set forth in claim 1, wherein the plane of said blade is disposed at an acute angle to the axes of said elongated members.

3. A device as set forth in claim 1, and further including a base plate on said base member, said base plate having an aperture to receive said blade, and means for adjusting the width of said aperture.

4. A device as set forth in claim 3, wherein the plane of said blade is disposed at an acute angle to the axes of said elongated members.

5. A device for forming slits in a sheet material, comprising a working surface, an aperture in said surface, a blade mounted above said surface, said blade having a plurality of cutting edges along the lower end thereof each having an effective work cutting portion terminating in a lowermost and leading work piercing point, successive work cutting portions being stepped away from said surface with the leading work piercing point of one effective cutting portion being spaced upwardly from the uppermost section of the preceding effective cutting portion, means for moving said blade to advance said edges toward said working surface and into said aperture, and means for adjusting the extent of movement of said blade to cause .electively one or more of said cutting edges to advance into said aperture, whereby the work piece is cut by one complete cutting portion before being pierced by any part of the next succeeding cutting portion and the cut of each cutting edge is commenced by a work piercing point.

6. A device as set forth in claim 5, and further including means for adjusting the size of said aperture receiving said blade.

7. A device as set forth in claim 5, wherein said working surface is disposed on an elongated base member, and the plane of said blade is disposed at an acute angle to the axis of the elongated base member.

8. In a device for forming slits in a sheet material, the combination including a working surface, an aperture in said surface. a blade, said blade having a plurality of graduated cutting edges along the lower end thereof, a support for said blade, means for moving said support and said blade to advance said cutting edges toward said working surface and into said aperture, a rotatable plate, a plurality of stops of varying height on said plate, means for rotating said plate to place one of said stops at a time in position to be contacted by said support on advance thereof, the height of said stops being so related to the height of said cutting edges as to cause one or more of said edges to advance into said aperture when said support makes contact with the respective stops.

9. In a device for forming slits in a sheet material, the combination including a working surface, an aperture in said surface, a blade, said blade having a plurality of sawtooth shaped graduated serrations along the lower end thereof, said serrations having inclined lower edges ter minating in a lowermost point, a support for said blade. means for moving said support and said blade to advance said serrations toward said working surface and into said aperture, a rotatable plate, a plurality of steps of varying height on said plate, means for rotating said plate to place one of said stops at a time in position to be contacted by said support on advance thereof, the height of said stops being so related to the height of said serrations as to cause one or more of said serrations to advance into said aperture when said support makes contact with the respective steps.

10. In a device for forming slits in asheet material,

the combination including a working surface, an aperture in said surface, a blade, said blade having a plurality of sawtooth shaped graduated serrations along the lower end thereof, said serrations having inclined lower edges terminating in a lowermost point, a support for said blade, means for moving said support and said blade to advance said serrations toward said Working surface and into said aperture, means for adjusting the size of said aperture to receive said blade, a rotatable plate, a plurality of stops of varying height on said plate, means for rotating said plate to place one of said stops at a time in position to be contacted by said support on advance thereof, the height of said stops being so related to the height of said serrations as to cause one or more of said serrations to advance into said aperture when said support makes contact with the respective stops.

11. A device for making slits in a work piece which comprises an elongated base member, an elongated upper member connected at one end to said base member and overhanging said base member and forming a space between said members for passage of a work piece through said space, said members being substantially coextensive, a working surface at the free end of said base member, an aperture in said surface, a support mounted at the free end of said upper member above said working surface, for sliding movement in a direction transversely of said members, a blade connected to said support and in alignment with said aperture, the plane of said blade being disposed at an angle to the axes of said elongated members, said blade having a plurality of graduated serrations along the lower end thereof, means for moving said sup port and said blade to advance said serrations toward said working surface and into said aperture, a rotatable plate, a plurlity of stops of varying height on said plate, means for rotating said plate to place one of said stops at a time in position to be contacted by said support on advance thereof, the height of said stops being so related to the height of said serrations as to cause one or more of said serrations to advance into said aperture when said support makes contact with the respective stops.

12. A device as defined in claim 11, wherein at least some of said serrations are sawtooth shaped and have inclined lower edges terminating in a lowermost point.

13. A device for making slits in a work piece which comprises an elongated base member, an elongated upper member connected at one end to said base member and overhanging said base member and forming a space between said members for passage of a work piece through said space, said members being substantially coextensive, a working surface at the free end of said base member, an aperture in said surface, a blade support block mounted at the free end of said upper member above said working surface, guides for said blade support block, said block slidably engaging said guides for movement of said block in a direction transversely of said members, a blade connected to said block, the plane of said blade being disposed substantially normal to said working surface, said blade having a plurality of serrations of graduated height along the lower end thereof, a spring biased member connected to said blade support block, said last named member normally biasing said blade support member and blade in an upward direction away from said working surface, a handle for contacting said spring biased member and urging it downward to move said support block and said blade to advance said serrations toward said working surface and into said aperture, a rotatable plate mounted below said blade support block and adjacent said working surface, a plurality of stops of varying height on said plate, means for rotating said plate to place one of said stops at a time in position to be contacted by the lower edge of said blade support block on advance thereof, and detents to lock said plate in position for aligning each of the respective stops thereon individually with said block, the height of said stops being so related to the height of said serrations as to cause one or more 9 10 of said serrations to advance into said aperture when said 310,602 McBeth J an. 13, 1885 blade support block makes contact with the respective 806,133 Graham Dec. 5, 1905 stops. 1,055,610 Church Mar. 11, 1913 1,669,344 Moore May 8, 1928 References Cited in the file of this patent 5 1,987,455 Washburn Jan. 8, 1935 UNITED STATES PATENTS 93,0 2 Olsen p 14, 1 7 2,396,814 Besag Mar. 19, 1946 70,033 Shopbell Oct. 22, 1867 

